Collagen and elastin in the dermis of the skin are the major components of the dermis, which determine the tensile strength of the skin. Collagen and fibroblasts interact with each other to exhibit high elasticity which keeps the skin tight and elastic. As aging continues, fibroblasts are more inactive, or the quality of collagen is reduced or the interaction between fibroblasts and collagen is lessened, and thus the skin loses elasticity, causing wrinkles.
Because the biggest factors that determine skin elasticity are the interaction and binding force between dermal collagen and fibroblasts, the interaction between collagen and fibroblasts was measured using a collagen gel contraction assay (Experimental Dermatology, 17, 788-789) in the prior art. Specifically, skin elasticity was evaluated by mixing fibroblasts with collagen to make gels, culturing the gels in general culture dishes, comparing the degree of contraction between the gels to determine the change in interaction between collagen and fibroblasts caused by a material, and calculating the surface area of each of the gels using digital images (photographs).
However, the above method has a disadvantage in that, because it shows two-dimensional results, it cannot visually show a three-dimensional change which can occur in the actual skin.